Manufacture of glass articles.



B. M. HANNA.

MANUFACTURE OF GLASS ARTICLES. APPLI OATION rum) DEC. 23, 1913.

3 6 1 0 Patented July 21, 1914.

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UNITED STATES PATENT OFFICE.

BENJAMIN M. HANNA, F PITTSBURGH, PENNSYLVANIA.

MANUFACTURE OF GLASS. ARTICLES.

Specification of Letters Patent. Patented J 1113 21, 1914:, Application filed December 23, 1913. l Serial No. 808,437.

' is a specification.

tion optically in course of time.

My inventionrelates to compound glass articles and consists ina method of unit ng the components. It has practlcal application in themaking of-bi-focal lenses, and,

while in broadest terms, my invention is not limited to lens-making, nor even to the field of optical instruments, I shall describe my invention in its application thereto.

In the accompanying drawings, which illustrate the invention, Figures ,1 and 2 show in section and .in plan two bodiesof glass united according to my invention; Figs. 3 and 4 are like views illustrating a variation in detail; Figs. 5 and 6show in section and plan a bi-focal spectacle lens made according to my improved method; while Figs. 7 and 8 show in plan variations in detail upon the showing of Fig. 6. I

The first four figures are diagrammatic. In them a body of glass 1 is applied to and secured in another body of glass 2 by the apv of oval form; the form is unimportant; but it will be noted that if the form be nonplication of the principle of thermal expansion. Ordinarily the union of two bodies of glass involves either the complete or localized fusion of the components, or the use of cement. The fusion of the parts of optical glasses when once they have been ground is destructive of or tends to the destruction of the shape which has been most exactly and laboriously produced; and the use of cement is objectionable, when applied over lens surfaces, because of its deteriora- But, ac-

- cording to my invention, the components,

one of which is to inclose wholly or in part the other, are most carefully ground and shaped and are then subjected to different degrees of temperature, the inclosing body being'brought to relatively high, and the inclosed body to relatively low'temperature. It will be understood that artificial application of heat or cold may be made to one or both bodies, separately ortogether. When so prepared, the components are brought togetherand allowed to come to uniform temperature, with the result that the inclosing body by its relative contraction will engage security.-

and securely hold the inclosed body. This mode of procedure cheap and simple and does notwrequire that an optician carry a .largeassortment of variously shaped lensparts,

In igs. 1 and 3 thebodiesengage one an other along an edge as; this edge may be rounded in convex or'concave curvature. In Fig. 1 there is a concavity, and-this concavity tends. togreater security of, union. The edge may if desired be straight, as in Fig. 3,I in case the specific increments of expansion and contraction of the particular qualitiesof glass employed are such as to afiord in this manner a union of suflicient The practice'of' my in-vention does not, it

will be understood, exclude the employment of cement or of other filling material also as an additional means of security, and if the applicationof cement or other material be confined to the edges of a lens its alteration through time can have no great effect upon the optical qualities of the instrument; furthermore, the presence of such material in the seamqmay be desirable as a .seal to prevent ingress of moisture or dust to space between lens surfaces, or to any sealed spaces. I

Figs. 2 and 4 show theinserted body to be circular, the turning of the inserted .body withrfelation to the matrix body is more effectively guarded against, and thisis an important consideration, in optical work.

Figs. 58 inclusive show the invention .in its application to bi-focal spectacle lenses. Figs. 5 and 6 will be fully understood from what has gone before; the presence of a cement over the lens surfaces which are brought together is rendered unnecessary. If the inserted lens is to extend to the margin of the glass, as shown in Fig. 7, its security may be assured by shaping the matrix-body with overhanging lips 3, to par-. tially inclose the inserted body, or serrations may be formed elsewhere as indicated at 4 in Fig. 8. In each case the inserted body or a part of it is 'wholly or partially inclosed and held against separationwhen once thetwo bodies have beenunited according to the method of thermal expansion already indicated. It remains to be noted of Figs. 7 and 8 (and also of an insert of the plan shown in Fig. 6) that in each case the orifice and 2 need not be shapedto conformity one to the other (as is usual when the components of the glass are cemented face to face) if, for other reasons, non-conformity shouldbe desired. This is consequent upon the'fact that the holding ofthe insert is, according to my invention, not due to the cementing of the parts face to face but to thatengagementalong the edge of the insert whichhas already been described.

While I have described a method which permits of uniting previously shaped parts, it will be understood that-thepr'acticebf my method doesnot forbid grinding or otherwise shapingthe composite .body after it has been {put together according to my im-' proved method. a

It will be' understood that the method is in no sense confined to use with glass of any specific quality or components 'of' s ecific qualities, but that in the matter of in ex of refraction (for example) the invention is quite independent of any"part-icularity'in that regard.

My use of'the term lass in this-specification and in the appen ed claims is not in tended to be a scientific definition of a product of the larts ,'butis rather used in a generic sense, and I intend it to be inclusive of material such as quartz for instance. And manifestly the invention is applicable to material of desired optical properties whatever its source and nature in other reunderstood that spects which hascertain physical characteristics-thatds to say, the; property ofexpanding and contracting under varying temperature. i

I claim as my invention: I I 1. The method herein described of unit-ing two bodies of glass'in solid state which consists in forming in one body a recess to receive the other, bringing the two'bodies to different degrees of temperature; applying the second body to the recess formed in the first when the twobodie's'are at such'difi'erent temperatures, and then allowing them to come to uniform temperature. V r

2. The method of making bi-fooal lenses which consistsingrinding the lens parts and forming in one lens part anorifice for receiving the other lens part, bringing the two parts to different degrees of temperature v i and then inserting one part in the orifice formed for it in the other lens part, and allowing the parts so brought together to'come to uniform temperature;

3. The method of making a bi-focal'lens which consists in forming 1n one lensrpart a recess extending part 'way through the depth of the other lens part, bringing the-two'parts, to different degrees of temperature, applyingra sealing substance to} the edgeof the part second named and inserting it in the recess formedfor it in the lens part first named, andthen allowing the united lens to come to uniform temperature. 3 Y Y g In testimony whereof I have'hereunto set my hand.

e BENJAMIN'M. HANNA. Witnesses:

FRANCIS J. ToMAssoN,i- BAYARD H. CHRISTI."

lens and shaped to receive the 

